As adhesives that are used for industrial applications and the like, acrylic adhesives including an acryl copolymer are generally used since the adhesives can be easily manufactured at low cost.
Adhesives need to have not only an adhesive force but also durability under a variety of conditions depending on applications. For example, even when used in high-temperature environments, adhesives need to be not easily misaligned from a subject to which an adherend is attached by external forces or the like (thermal creep resistance).
In the case of operating an electrostatic capacitance-type touch panel display or the like, there are cases in which static electricity generated on the front panel reaches the touch panel as a leak current and the static electricity is applied to the touch panel. Therefore, adhesives that are used to attach front panels and touch panels need to have insulation breakdown resistance so as to prevent static electricity from reaching touch panels. In recent years, there has been a tendency that the area or thickness of adhesive layers decreases in response to the size reduction of displays or an increase in the size of screens, and thus there is a demand for improving the insulation breakdown resistance of adhesives.
Patent Document 1 discloses a highly insulating heat-diffusive sheet made of a composition in which a thermoplastic elastomer, a thermoplastic resin, and, as a binder, one or more polymers selected from the group consisting of acryl rubber and acrylic adhesives are used and 50% to 90% by volume of boron nitride having a flat shape having an aspect ratio of 10 to 1,000 is blended as a heat diffusion filler into the binder.
Patent Document 2 discloses a flame-retardant heat-resistant adhesive tape capable of suppressing carbonization insulation breakdown which includes a support having one or more layers made of a polyester polyurethane resin crosslinked by a polyisocyanate-based crosslinking agent laminated on at least one surface of an impregnation sheet formed by impregnating the resin in a non-woven fabric and an adhesive layer made of an acrylic adhesive or the like which is provided on at least one surface of the support.